Undefined symbol "__sbmaskrune"

Upgraded to 6.2-stable (and got 6.3-prerelease) today. Needed to upgrade
amavisd-new, and that required upgrading p5-Convert-UUlib. (All done from
ports.)
Unfortunately, when amavisd runs, it produces this error now:
/libexec/ld-elf.so.1: /usr/local/lib/perl5/site_perl/5.8.6/mach/auto/Convert/UUlib/UUlib.so: Undefined symbol "__sbmaskrune"
I'm not sure where this symbol is supposed to be found, but it's
referenced in a great many other libraries which don't seem to be having
any problems with linking or finding that symbol.
Any ideas what could be going wrong? I'm at a loss for even how to begin
tracking this down...
Nick